package com.liwei.schedule.DelayedTasker;

import static java.util.concurrent.TimeUnit.NANOSECONDS;
import static java.util.concurrent.TimeUnit.SECONDS;

import java.util.Collection;
import java.util.Collections;
import java.util.Random;
import java.util.concurrent.DelayQueue;
import java.util.concurrent.Delayed;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

public class DelayedTasker implements Runnable {
    DelayQueue<DelayedTask> queue = new DelayQueue<DelayedTask>();

    public void addTask(DelayedTask e) {
        queue.put(e);
    }

    public void removeTask() {
        queue.poll();
    }

    public Collection<DelayedTask> getAllTasks() {
        return Collections.unmodifiableCollection(queue);
    }

    public int getTaskQuantity() {
        return queue.size();
    }

    public void run() {
        while (!queue.isEmpty())
            try {
                queue.take().run();
            } catch (InterruptedException e) {
                System.out.println("Interrupted");
            }
        System.out.println("Finished DelayedTask");
    }

    public static class DelayedTask implements Delayed, Runnable {
        private static int counter = 0;
        private final int  id      = counter++;
        private final int  delta;
        private final long trigger;

        public DelayedTask(int delayInSeconds) {
            delta = delayInSeconds;
            trigger = System.nanoTime() + NANOSECONDS.convert(delta, SECONDS);
        }

        public long getDelay(TimeUnit unit) {
            return unit.convert(trigger - System.nanoTime(), NANOSECONDS);
        }

        public int compareTo(Delayed arg) {
            DelayedTask that = (DelayedTask) arg;
            if (trigger < that.trigger)
                return -1;
            if (trigger > that.trigger)
                return 1;
            return 0;
        }

        public void run() {
            System.out.println((System.currentTimeMillis() / 1000) % 1000);
            //run all that you want to do
            System.out.println(this);
        }

        public String toString() {
            return "[" + delta + "s]" + "Task" + id;
        }
    }

    public static void main(String[] args) {
        Random rand = new Random();
        ExecutorService exec = Executors.newCachedThreadPool();
        DelayedTasker tasker = new DelayedTasker();
        for (int i = 0; i < 10; i++) {
            int diff = rand.nextInt(20);
            System.out.println("task" + i + "---" + diff);
            tasker.addTask(new DelayedTask(diff));
        }
        exec.execute(tasker);
        System.out.println((System.currentTimeMillis() / 1000) % 1000);
        exec.shutdown();
    }
}
